DapperLib / Dapper.Contrib

Dapper community contributions - additional extensions for Dapper
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Dapper.Contrib - a simple object mapper for .Net

Build status

Release Notes

Located at dapperlib.github.io/Dapper.Contrib

Packages

MyGet Pre-release feed: https://www.myget.org/gallery/dapper

Package NuGet Stable NuGet Pre-release Downloads MyGet
Dapper.Contrib Dapper.Contrib Dapper.Contrib Dapper.Contrib Dapper.Contrib MyGet

Features

Dapper.Contrib contains a number of helper methods for inserting, getting, updating and deleting records.

The full list of extension methods in Dapper.Contrib right now are:

T Get<T>(id);
IEnumerable<T> GetAll<T>();
int Insert<T>(T obj);
int Insert<T>(Enumerable<T> list);
bool Update<T>(T obj);
bool Update<T>(Enumerable<T> list);
bool Delete<T>(T obj);
bool Delete<T>(Enumerable<T> list);
bool DeleteAll<T>();

For these extensions to work, the entity in question MUST have a key property. Dapper will automatically use a property named "id" (case-insensitive) as the key property, if one is present.

public class Car
{
    public int Id { get; set; } // Works by convention
    public string Name { get; set; }
}

If the entity doesn't follow this convention, decorate a specific property with a [Key] or [ExplicitKey] attribute.

public class User
{
    [Key]
    int TheId { get; set; }
    string Name { get; set; }
    int Age { get; set; }
}

[Key] should be used for database-generated keys (e.g. autoincrement columns), while [ExplicitKey] should be used for explicit keys generated in code.

Get methods

Get one specific entity based on id

var car = connection.Get<Car>(1);

or a list of all entities in the table.

var cars = connection.GetAll<Car>();

Insert methods

Insert one entity

connection.Insert(new Car { Name = "Volvo" });

or a list of entities.

connection.Insert(cars);

Update methods

Update one specific entity

connection.Update(new Car() { Id = 1, Name = "Saab" });

or update a list of entities.

connection.Update(cars);

Delete methods

Delete an entity by the specified [Key] property

connection.Delete(new Car() { Id = 1 });

a list of entities

connection.Delete(cars);

or ALL entities in the table.

connection.DeleteAll<Car>();

Special Attributes

Dapper.Contrib makes use of some optional attributes:

Limitations and caveats

SQLite

SQLiteConnection exposes an Update event that clashes with the Update extension provided by Dapper.Contrib. There are 2 ways to deal with this.

  1. Call the Update method explicitly from SqlMapperExtensions

    SqlMapperExtensions.Update(_conn, new Employee { Id = 1, Name = "Mercedes" });
  2. Make the method signature unique by passing a type parameter to Update

    connection.Update<Car>(new Car() { Id = 1, Name = "Maruti" });